In electrophotography, an electrophotographic substrate containing a photoconductive insulating layer on a conductive layer is imaged by first uniformly electrostatically charging a surface of the substrate. The substrate is then exposed to a pattern of activating electromagnetic radiation, such as, for example, light. The electromagnetic radiation selectively dissipates charge in illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image in non-illuminated areas of the photoconductive insulating layer. This electrostatic latent image is then developed to form a visible image by depositing finely divided electroscopic marking particles on the surface of the photoconductive insulating layer. The resulting visible image is then transferred from the electrophotographic substrate to a necessary member, such as, for example, an intermediate-transfer member or a print substrate, such as paper. This image developing process can be repeated as many times as necessary with reusable photoconductive insulating layers.
In image-forming apparatus such as copiers, printers, and facsimiles, electrophotographic systems in which charging, exposure, development, transfer, etc., are carried out using electrophotographic photoreceptors have been widely employed. In such image-forming apparatus, there are ever-increasing demands for speeding up of image-formation processes, improvement in image quality, miniaturization and prolonged life of the apparatus, reduction in production cost and running cost, etc. Further, with recent advances in computers and communication technology, digital systems and color-image output systems have been applied also to the image-forming apparatus.
Electrophotographic imaging members (such as photoreceptors) are known. Electrophotographic imaging members are commonly used in electrophotographic processes having either a flexible belt or a rigid drum configuration. These electrophotographic imaging members sometimes comprise a photoconductive layer including a single layer or composite layers. These electrophotographic imaging members take many different forms. For example, layered photoresponsive imaging members are known in the art. U.S. Pat. No. 4,265,990 to Stolka et al. describes a layered photoreceptor having separate photogenerating and charge-transport layers. The photogenerating layer disclosed in Stolka is capable of photogenerating holes and injecting the photogenerated holes into the charge-transport layer. Thus, in the photoreceptors of Stolka, the photogenerating material generates electrons and holes when subjected to light.
More advanced photoconductive photoreceptors containing highly specialized component layers are also known. For example, a multi-layered photoreceptor employed in electrophotographic imaging systems sometimes includes one or more of a substrate, an undercoating layer, an intermediate layer, an optional hole- or charge-blocking layer, a charge-generating layer (including a photogenerating material in a binder) over an undercoating layer and/or a blocking layer, and a charge-transport layer (including a charge-transport material in a binder). Additional layers such as one or more overcoat layer or layers are also sometimes included.
In view of such a background, improvement in electrophotographic properties and durability, miniaturization, reduction in cost, and the like, in electrophotographic photoreceptors have been studied, and electrophotographic photoreceptors using various materials have been proposed.
Production of a number of arylamine compounds, such as arylamine compounds that are useful as charge-transport compounds in electrostatographic imaging devices and processes, often involves synthesis of intermediate materials, some of which generally are costly and/or time-consuming to produce, and some of which involve a multi-step process.
One such class of intermediate products are diarylamines, which may be reacted with halogenated aryl compounds to form a variety of triarylamine compounds. See, for example, U.S. patent application Ser. No. 10/992,690 filed Nov. 22, 2004. Currently, diarylamines are typical produced from anilines using so-called Goldberg reaction chemistry. The formation of diphenylamines using the Goldberg reaction takes three reaction steps, and thus can be a lengthy process. Diarylamines may also be produced by subjecting an arylamine to condensation reaction in the co-presence of anhydrous aluminum chloride and anhydrous calcium chloride, as described in U.S. Pat. No. 6,218,576 B1 to Shintou et al. Both of these methods require high temperatures and harsh reaction conditions. The purity of the diarylamines obtained from these two reactions are generally low, requiring lengthy and costly purification processes.
Accordingly, improved processes providing safe, cost-effective, and efficient methods for diarylamine production are desired.